The commander in chief lamented on Thursday afternoon that the Republicans have been unable to follow through on their campaign promises of repealing and replacing the Affordable Care Act, better known as Obamacare. In a series of tweets, he suggested this failure gave Vermont Sen. Bernie Sanders an opening to advance his plan for a single-payer health care system, also known as Medicare for All, which Trump denounced as “a curse” on the United States and the American people.

But Trump assured fellow Republicans that he would save the country from this fate by vetoing any single-payer health care legislation that comes across his desk.

Bernie Sanders is pushing hard for a single payer healthcare plan – a curse on the U.S. & its people…

This is far from the first time Trump has chided Republicans in Congress for coming up short in their efforts toward health care reform or attacked Sanders for his Democratic Socialist ideals and proposals.

Earlier Thursday, aboard Air Force One from Fort Myers, Fla., to Washington, D.C., Trump criticized Sen. John McCain, R-Ariz., for the health care defeat. In late July, McCain effectively killed the GOP replacement plan, known as the Health Care Freedom Act, by joining two other Republicans (Sen. Susan Collins of Maine and Sen. Lisa Murkowski of Alaska) who opposed the plan — ending in a 49-51 vote.

“It was a very unpleasant surprise,” Trump told reporters. “Now we have people talking about single-payer. So Republicans have to stick together better. We had the votes. John McCain changed his mind, pure and simple. If the Republicans don’t stick together, then I’m going to have to do more and more.”

Sanders has long been a supporter of universal health care and introduced his Medicare for All bill in the Senate on Wednesday, boasting that it already has 15 co-sponsors and the support of dozens of grassroots organizations.

“Now I know that taking on the insurance companies and Wall Street and the drug companies and the medical equipment suppliers — all those people who profit off our dysfunctional health care system — is not going to be easy fight,” he said in a video. “And the only way that we win this is when the American people stand up as they are and demand real change.”